Abstract: A method for adding at least one additional image frame to a stream of encoded image frames, the stream of encoded image frames comprising image frames encoded by an encoder. An event relating to at least one of: i) a change of operation state of a sender of the stream of encoded image frames, or ii) a change of connection state between the sender and a receiver is detected. Depending on the type of the detected event, the at least one additional image frame is provided. Each at least one additional image frame comprises a reference to a preceding image frame and codes a predetermined visual change relative to the preceding image frame. The predetermined visual change is indicative of the type of the detected event. The at least one additional image frame is added to the stream of encoded image frames to obtain a combined stream of image frames.

Abstract: A method for forming a combined image frame of a combined video stream comprises: capturing image frames of first and second video streams; encoding image data of the image frames of the first and second video streams, wherein each image frame of the first and second video streams are respectively encoded into first and second encoded data comprising a plurality of rows wherein each row has a height of a single coding unit and a width equal to a width of the image frame and is encoded as one or more slices; and combining the first and second encoded data into combined encoded data by interleaving rows of the first and second encoded data. The combined encoded data representing the combined image frame of the combined video stream.

Abstract: An encoding device and a method for encoding an image frame comprising a plurality of pixel blocks are provided. A respective offset compression value is set for each of the plurality of pixel blocks based on an interest level associated with the pixel block, wherein each offset compression value defines an offset in relation to a reference compression value set for the image frame. In the image frame, one or more low contrast regions having a contrast which is below a predefined contrast threshold are identified. For pixel blocks within the one or more low contrast regions having set offset compression values based on the associated interest levels higher than a predefined offset compression threshold, the set offset compression values are selectively restricted to be at most equal to the predefined offset compression threshold. The image frame is then encoded using the set offset compression values.

Abstract: A method for forming a combined image frame of a combined video stream comprises: capturing image frames of first and second video streams; encoding image data of the image frames of the first and second video streams, wherein each image frame of the first and second video streams are respectively encoded into first and second encoded data comprising a plurality of rows wherein each row has a height of a single coding unit and a width equal to a width of the image frame and is encoded as one or more slices; and combining the first and second encoded data into combined encoded data by interleaving rows of the first and second encoded data. The combined encoded data representing the combined image frame of the combined video stream.

Abstract: A method of controlling output bitrate of a video encoder encoding a video sequence comprises: setting an allowable average bitrate, gathering encoding data by encoding video during a first time period and for each of a plurality of time intervals, storing a respective output bitrate, and a quantisation parameter used for encoding during the respective time interval. For each time interval, the output bitrate is normalised by calculating a corresponding normalised bitrate estimated for a predetermined nominal quantisation parameter as a function of the output bitrate and the quantisation parameter. An average normalised bitrate is calculated by averaging the normalised bitrates of the plurality of time intervals. A new quantisation parameter is calculated based on a comparison of the average normalised bitrate and the allowable average bitrate. The video sequence is encoded using the new quantisation parameter during a second time period subsequent to the first time period.

Abstract: Encoding video data comprises receiving an image sequence comprising first and second input image frames, adding an overlay, thereby generating first and second generated image frames, and encoding a video stream containing output image frames with and without overlay. The first input image frame is encoded as an intra-frame to form a first output image frame. The second input image frame is encoded as an inter-frame with reference to the first output image frame to form a second output image frame. The generated image frames are encoded as inter-frames with reference to the first and second output image frames to form first and second overlaid output image frames. A first part of the second generated image frame is encoded with reference to the first overlaid output image frame, and a second part of the second generated image frame is encoded with reference to the second output image frame.

Abstract: A method for encoding video is disclosed wherein information representative of pixels in an image frame is received, and a spatial statistical measure of said information is calculated for groups of neighbouring pixels to form a group value for each group of pixels. A set of available quantization steps is determined comprising a first predetermined quantization step. For a first group of neighbouring pixels, the method comprises: for each available quantization step calculating a remainder after division of the group value of the first group of pixels by the respective available quantization step. The quantization step of the set that results in the smallest remainder is selected as selected quantization step. The first group of pixels is encoded using the selected quantization step. A method of encoding differences between image frames is also disclosed, as well as encoding systems.

Abstract: A method, a controller, and a system for encoding a sequence of video frames captured by a camera mounted to a moving object. The method comprises receiving input indicating an amount of movement of the camera, receiving input regarding a predetermined distance, and selecting between intra-coding and inter-coding of the video frames of the sequence based on the amount of movement of the camera and the predetermined distance, such that the camera moves at most the predetermined distance between capturing video frames which are intra-coded.

Abstract: A method of controlling output bitrate of a video encoder encoding a video sequence comprises: setting an allowable average bitrate, gathering encoding data by encoding video during a first time period and for each of a plurality of time intervals, storing a respective output bitratet, and a quantisation parameter used for encoding during the respective time interval. For each time interval, the output bitrate is normalised by calculating a corresponding normalised bitrate estimated for a predetermined nominal quantisation parameter as a function of the output bitrate and the quantisation parameter. An average normalised bitrate is calculated by averaging the normalised bitrates of the plurality of time intervals. A new quantisation parameter is calculated based on a comparison of the average normalised bitrate and the allowable average bitrate. The video sequence is encoded using the new quantisation parameter during a second time period subsequent to the first time period.

Abstract: A method of adding comfort noise to a video sequence comprising setting parameters of a deblocking filter of a video encoder to change values during the video sequence, encoding frames of the video sequence using the parameters of the deblocking filter that are set to change values during the video sequence, thereby introducing comfort noise in the video sequence, and including the encoded frames in a bitstream together with an indication of which parameters of the deblocking filter were used when encoding the frames of the video sequence.

Abstract: A method of controlling output bitrate of a video encoder encoding a video sequence. The method comprises setting a long-term bit budget for a time period of at least one day for output of the video encoder, and determining a first allowable bitrate based on the long-term bit budget. The method further comprises determining an instantaneous bit restriction for output of the video encoder, and determining a second allowable bitrate based on the instantaneous bit restriction. Output bitrate is controlled based on the first allowable bitrate and the second allowable bitrate, such that the long-term bit budget, the first allowable bitrate and the second allowable bitrate are complied with. The method may be performed in a non-transitory computer-readable medium having instruction stored thereon. The method may also be performed by a bitrate controller. The bitrate controller may be found in a camera and a network video recorder.

Abstract: Encoding video data comprises receiving an image sequence comprising first and second input image frames, adding an overlay, thereby generating first and second generated image frames, and encoding a video stream containing output image frames with and without overlay. The first input image frame is encoded as an intra-frame to form a first output image frame. The second input image frame is encoded as an inter-frame with reference to the first output image frame to form a second output image frame. The generated image frames are encoded as inter-frames with reference to the first and second output image frames to form first and second overlaid output image frames. A first part of the second generated image frame is encoded with reference to the first overlaid output image frame, and a second part of the second generated image frame is encoded with reference to the second output image frame.

Abstract: A method, a controller, and a system for encoding a sequence of video frames captured by a camera mounted to a moving object. The method comprises receiving input indicating an amount of movement of the camera, receiving input regarding a predetermined distance, and selecting between intra-coding and inter-coding of the video frames of the sequence based on the amount of movement of the camera and the predetermined distance, such that the camera moves at most the predetermined distance between capturing video frames which are intra-coded.

Abstract: A method of adding comfort noise to a video sequence comprising setting parameters of a deblocking filter of a video encoder to change values during the video sequence, encoding frames of the video sequence using the parameters of the deblocking filter that are set to change values during the video sequence, thereby introducing comfort noise in the video sequence, and including the encoded frames in a bitstream together with an indication of which parameters of the deblocking filter were used when encoding the frames of the video sequence.

Abstract: A method of controlling output bitrate of a video encoder encoding a video sequence. The method comprises setting a long-term bit budget for a time period of at least one day for output of the video encoder, and determining a first allowable bitrate based on the long-term bit budget. The method further comprises determining an instantaneous bit restriction for output of the video encoder, and determining a second allowable bitrate based on the instantaneous bit restriction. Output bitrate is controlled based on the first allowable bitrate and the second allowable bitrate, such that the long-term bit budget, the first allowable bitrate and the second allowable bitrate are complied with. The method may be performed in a non-transitory computer-readable medium having instruction stored thereon. The method may also be performed by a bitrate controller. The bitrate controller may be found in a camera and a network video recorder.

Abstract: A method for encoding video is disclosed wherein information representative of pixels in an image frame is received, and a spatial statistical measure of said information is calculated for groups of neighbouring pixels to form a group value for each group of pixels. A set of available quantization steps is determined comprising a first predetermined quantization step. For a first group of neighbouring pixels, the method comprises: for each available quantization step calculating a remainder after division of the group value of the first group of pixels by the respective available quantization step. The quantization step of the set that results in the smallest remainder is selected as selected quantization step. The first group of pixels is encoded using the selected quantization step. A method of encoding differences between image frames is also disclosed, as well as encoding systems.